| 摘要 |
PROBLEM TO BE SOLVED: To prevent hauling at the time of setting a microphone and a speaker for transmitting and receiving a transmission signal and a reception signal for communication when placed close to each other. SOLUTION: In a loud-speaker communication equipment for communicating with one terminal AQ1 and the other terminal BQ1, one terminal is provided with a microphone MIC1 to which a power is supplied through a microphone load circuit 1 for transmitting a transmission signal through a microphone amplifier 2 to the other terminal, and a speaker SP1 for receiving a reception signal from the terminal. The microphone load circuit of one terminal prevents hauling due to feedback from the speaker SP1 to the microphone MIC1 by using an LC tuning circuit 11. The microphone load circuit is constituted of a parallel circuit constituted of the LC tuning circuit substantially tuning with signal frequencies 1.5-3.0 kHz and a high resistance R1.
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